Have you observed an ORA-0600 or ORA-07445 reported in your alert log?

The ORA-600 error is the generic internal error number for Oracle program exceptions. It indicates that a process has encountered a low-level, unexpected condition.

The ORA-600 error statement includes a list of arguments in square brackets:

ORA 600 "internal error code, arguments: [%s], [%s],[%s], [%s], [%s]"

The first argument is the internal message number or character string. This argument and the database version number are critical in identifying the root cause and the potential impact to your system.  The remaining arguments in the ORA-600 error text are used to supply further information (e.g. values of internal variables etc).

Looking for the best way to diagnose?

There is an ORA-600 Troubleshooter Tool available in My Oracle Support.  This tool will lead you to applicable content in My Oracle Support on the problem and can be used to investigate the problem with argument data from the error message or you can pull out the first 10 or 15 stack pointers from the associated trace file to match up against known bugs.

Note 153788.1 ORA-600/ORA-7445 Troubleshooter
Note 1082674.1 A Video To Demonstrate The Usage Of The ORA-600/ORA-7445 Lookup Tool [Video]

Also, take a quick look at the Master Note for Diagnosing ORA-600 ( MasterNoteORA600.docx) for some tips on diagnosing.